[Cbc] CBC significant different running times with the same instance and executable

[Ted Ralphs]

Are you running in parallel or sequential mode? Parallel execution can be
non-deterministic and may exhibit the variance you are seeing, depending on
the parameters.

Ted

On Mon, Jan 27, 2020 at 12:10 PM Rita Portugal <rita at siscog.pt> wrote:

> Hi,
>
> My name is Rita Portugal
>
> I've been working with CBC "inside" C++ language in Visual Studio
> framework.
>
> I'm having some strange behavior that I'm hopping you could help me on
> understanding it.
>
> I read the input data, create a linear integer model than call
> branchAndBound.
>
> I started by testing a very small example to understand running time
> behavior but, while running the same instance and the same solver
> configuration several different times (in the same machine) I'm keep having
> different time results for getting the same optimal solution (between 5
> minutes to 25).
>
> When reading the user guide I understand that CBC has random components
> during is running process that can be desactivate by the
> setRandomSeed(7777) comand. But even doing that the behavior is still the
> same.
>
> Can you please advise me about any other possible responsable components
> for having such a different behavior between runnings?
>
> Thank you in advance
> --
>
> Rita Portugal
> Software Engineer
>
> *SISCOG - Sistemas Cognitivos, SA*
> Campo Grande, 378 - 3º, 1700-097 Lisboa • Portugal
> Tel: +351 217 529 100 • Fax: +351 217 529 101
>
>
> *www.siscog.pt* <http://www.siscog.pt>
>
> *"Optimising the resources of the world"*
>
>
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-- 
Dr. Ted Ralphs
Professor, Industrial and Systems Engineering
Lehigh University
(610) 628-1280
ted 'at' lehigh 'dot' edu
coral.ie.lehigh.edu/~ted
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